Moving POT to Optimization section in index.md and replacing Toolkit by Tool in a few places (#4272)

* Update get_started_dl_workbench.md

POToolkit => POTool

* Update QuantizedNetworks.md

POToolkit => POTool

* Moving POT to optimizations section

Moving POT to optimizations section

docs/get_started/get_started_dl_workbench.md

@@ -13,7 +13,7 @@ OpenVINO™ toolkit components:
 with pre-trained models for a range of different tasks
 * [Model Optimizer](../MO_DG/Deep_Learning_Model_Optimizer_DevGuide.md) to transform models into
 the Intermediate Representation (IR) format
-* [Post-Training Optimization toolkit](@ref pot_README) to calibrate a model and then execute it in the
+* [Post-training Optimization Tool](@ref pot_README) to calibrate a model and then execute it in the
  INT8 precision
 * [Accuracy Checker](@ref omz_tools_accuracy_checker) to determine the accuracy of a model
 * [Benchmark Tool](@ref openvino_inference_engine_samples_benchmark_app_README) to estimate inference performance on supported devices
@@ -136,4 +136,4 @@ For detailed instructions to create a new project, visit the links below:
 * [Inference Engine Developer Guide](../IE_DG/Deep_Learning_Inference_Engine_DevGuide.md)
 * [Model Optimizer Developer Guide](../MO_DG/Deep_Learning_Model_Optimizer_DevGuide.md)
 * [Inference Engine Samples Overview](../IE_DG/Samples_Overview.md)
-* [Overview of OpenVINO™ Toolkit Pre-Trained Models](https://software.intel.com/en-us/openvino-toolkit/documentation/pretrained-models)
+* [Overview of OpenVINO™ Toolkit Pre-Trained Models](https://software.intel.com/en-us/openvino-toolkit/documentation/pretrained-models)